Mechanical motion induced EMI on mobile synchronous generators

This paper presents the results of some experimental EMC tests performed on different mobile synchronous generators. These results show that, besides normal EMI generated by rectifying diodes in the field current circuit, additional noise raises from mechanical vibration of electric connection devices and friction between different insulating materials. Further investigations demonstrate that such vibration-derived EMI depends on connectivity of both of inner and outer wire connectors, where load and field currents are flowing. The experiments reveal these additional EMI generating mechanisms by comparing the synchronous generator EMI before and after proper modifications of the power cable connection and layout. Also rubbing different insulating materials can produce static electricity discharge, which results in additional EMI source. Further suggestions for EMI reduction are also discussed.